The Contribution of
Visualisation to
Scenario Thinking
24-08-2015
Hannah Dorothea Boomsma (10653449)
Msc in Forensic Science, University of Amsterdam
Research is performed at the Netherlands Forensic Institute
Laan van Ypenburg 6, 2497 GB Den Haag
February - August 2015
Examiner: Radboud Winkels (UvA)
Supervisor: Jurrien Bijhold (NFI)
Forensic Science International
Abstract
In existing literature the added value of visualisations over text is widely accepted. Regarding to scenario thinking, the contribution of visualisation that is mentioned, is in testing the scenarios. In the current study the other contributions visualisation could have in the scenario process are explored by answering the research question "Can visualisations contribute to scenario thinking in the different stages of the investigation to a deadly shooting incident?". To answer this question, a triangulation of method is applied; the participating observation, the semi-structured interview and a document analysis.
From this research several things can be concluded. First of all, it can be concluded that one should speak of activities instead of scenarios in order to obtain information concerning the scenario thinking process in a case. Secondly, the insight is gained that crime scene investigators should become more involved in the development of the criminal investigation to contribute to the continuing scenario process. Thirdly, there has been showed that early visualisation of three-dimensional point clouds and Bipeds can contribute in the formulation of scenarios. Therefore, it can be concluded that visualisations can have an added value in as well the formulation as the testing of scenarios. Finally, multiple suggestions are done for future research.
1. Introduction
Modern society has been depending on digital resources for some time now. Using digital resources has become part of our everyday life. Due to the quick development of the digital media technologies, the society is increasingly relying on images and other visualisations [1].
While visualisation in court are not common practise yet, it is an upcoming phenomenon in the forensic field. According to Dubelaar & Vanderveen [2] and Vanderveen & Roosma [3], judges, public prosecutors and lawyers acknowledge the added value that visualisations can have in the forensic process. An important application of visualising a crime scene, mentioned throughout literature, is testing certain scenarios that are considered to be feasible. During the reconstruction of a case using visualisations, it might become clear whether a certain scenario would be plausible [2,4,5,6].
According to literature, a visualised reconstruction might make it possible to exclude certain scenarios [2,4,5,6]. However, the current literature does not elaborate on 'how' to visualize these scenarios and does not mention contributions in other stages of the scenario handling process.
The technology supporting visualisation is an ongoing developing process, which not only results in an increase in the amount of visualisations, but also in an increase in the types of visualisations [7]. Within the forensic field, also an increasing diversity of visualisation technologies becomes available, such as three-dimensional visualisation of crime scenes. One of the advantages of using visualisations, compared to the traditional way of presenting information using words, is that visualisations are usually easier to understand. The complete concept can only be understood when the entire text is read [1]. This is different where images or other visualisations are applied. Visually examining an image, the primary vision is the overall picture; the compilation of all information that it encompasses. Secondly this vision needs to be traced back to individual pieces of information, while unavoidably keeping the overall picture in mind [1]. An image or visualisation can transfer more information in a limited period of time with little effort. That emphasizes the saying "A picture is worth a thousand words" [1].
Akkus [5] describes three main functions of the use of three-dimensional visualisations:
Providing insight in the incident, especially when the incident is difficult to scrutinize based on pure verbal explanation [8]. Three-dimensional visualisations ease the understanding of complicated matters and make it possible to represent many events in a limited period of time. Furthermore, a three-dimensional visualisation can clarify elements that require a certain
expertise which not all participants are familiar with (e.g. a judge might not have deep knowledge of forensic science).
The possibility to test witness statements and to hypothesise and test the scenarios.
Preserve the crime scene. Using a three-dimensional model, it is possible to play the situation over and over again, even though the real crime scene is not available anymore [5,9].
Schofield and Fowle [10] state that by using visualisation, the comprehension of the matter is increased and the efficiency in transferring information is enhanced, due to the little effort that is necessary to understand complex information. Furthermore, they name persuasiveness and attention increase as advantages of the visualisation technology. Lederer and Solomon [11] showed that people are twice as likely to be persuaded when arguments are supported by visual aids. Therefore, it can be assumed that visualisations increase the persuasiveness. The advantage of attention increase is based on the fact that attention is drawn to visualisations more easily than to written and spoken words. According to Schofield [12], actions draw attention most easily, followed by objects, pictures, diagrams, written and spoken words. Increased attention could result in studying the evidence more intensely, which could increase the understanding of the matter [10].
Concluding, there are many advantages of using visualisations such as three-dimensional models. These advantages could be extremely helpful in investigating deadly shooting incidents, because of their complexity and the amount of spatial information that could be visualised. During the study of Kieboom [6] within a project about three-dimensional visualisations of deadly shooting incidents, a procedure has been created for combining and visualising all the information around the incident. The resulting product was a presentation that could be used during meetings of different experts. Misunderstandings and interpretations could be minimised by consolidating all the available information and sharing the consolidated information with all parties. The visualisations were used to clarify the information. This supports all parties in understanding the outcomes of the investigations as various expertises are involved. Visualising and highlighting the most important parts of various investigations ensures that the key messages of the particular investigations are easier accessible.
In this research is tried to answer the main question "Can visualisations contribute to scenario thinking in the different stages of an investigation to a deadly shooting incident?". Here the term scenario thinking refers to the process of hypothesising and testing scenarios.
In the study of Kieboom [6] was aimed at the realisation of a digital format with three-dimensional visualisations to present all information within a forensic investigation that had been finished. One may expect that the preparation of all expert reports and the creation of a three-dimensional model takes a lot of time, and is therefore not available yet in an early stage of an investigation. However, it could be helpful to have other types of visualisations in this stage of an investigation. Therefore, in this study other types of visualisation have been tested for this purpose. In order to get a better understanding of what role visualisations could have in scenario thinking, the process of decision making in two actual cases has been monitored and analysed. In these cases was determined when scenarios came into play and how these could be obtained and visualised. In order to perform this research, three-dimensional modelling skills has been acquired.
In the next sections, the methods used will be explained that include participating observation, semi-structured interviews and a internal documents analysis. Results are presented and discussed, and multiple suggestions for further research are offered in the final chapter. In course of this research valuable information was obtained about a project within the police regarding placing a tactical analyst on the crime scene. Because insights that were gained in this project have used during the interviews, an explanation of this project is given in section 3.2.1 of the results.
2. Materials & Methods
The current study is an empirical and qualitative research into the process of scenario thinking and the contribution that visualisations can have on this process during the different stages of the investigation applied to a deadly shooting incident. This research uses a triangulation of methods, which means that the empirical measurements are taken from three different perspectives. According to Boeije [13] triangulation of methods will strengthen the results and interpretations in the research. The three methods that are applied in this study are participating observation, semi-structured interviews and an
analysis of documents. Firstly, the participating observation method is explained including an explanation of the project that was participated in and of the techniques that were used during the participation. Next, the semi-structured interviews are described. Here will be mentioned who the participants were, what they were questioned about and how the visualisations were created that were used during these interviews. Finally, the internal documents analysis will be explained.
2.1 Participating observation
Participating observation makes it possible to get an ultimate inside view of the field of interest in the study. When participating in the field of interest, one can observe very closely the different roles and procedures that are involved. Furthermore, due to this participation, one easily gets in touch with people in the field of interest that could provide additional knowledge and insights. In this research was participated in the project three-dimensional visualisations of deadly shooting incidents. The objective of this project is to get a product in which all information in the case is combined and all spatial information is presented in a three-dimensional visualisation. The project was started by the Netherlands police, the Netherlands Forensic Institute (NFI) and the radiology department of the academic hospital in Maastricht. Therefore, the expertises of visualisation and reconstruction, gunshot residue, firearms and ammunition, forensic radiology and pathology are incorporated in the project. The experts stay responsible for the correctness and completeness of the product. The
three-dimensional visualisation could be used by the investigating team to phrase additional questions that may open up new directions of the investigation and to assess different scenarios. After validation, the product could be used in court as a piece of evidence which could help the judge in determining his verdict.
Because of the interest in both visualisation and scenarios in the project, the project three-dimensional visualisations of deadly shooting incidents very well suited the current study. Therefore, participating in this project could give insight in the way visualisations and scenarios are used in the investigation of a case. Furthermore, the participation creates insight in the procedures within the investigation of a case and there could be noticed whether the role of visualisation and scenario thinking could be improved. Although Kieboom [6] has described which investigations should be done and how to build the three-dimensional model and interactive presentation that form the end product of the project, there is no procedure for obtaining the necessary information to create the end product. During the current study, for the first time, an on-going case was processed in the project which created the opportunity to describe the entire procedure. Through participating in this case, it was observed in which stages of the investigation certain information, such as the considered scenarios, becomes available. It was also observed what kind of visualisations could be developed in these stages.
In the participation, an active role was taken to get optimally involved in the procedures within the project and the investigation of the case. My role was to collect the available information including reports and pictures of the forensic investigation team of the police, reports of different expertises of the Netherlands Forensic Institute, the three-dimensional data of the crime scene and the data and reports of the radiology department which scanned the body of the victim. This information was analysed and combined in an interactive presentation in accordance with the experts that wrote the reports. Furthermore, visualisations that presented the spatial information from the reports were created using the three-dimensional modelling software. These tasks were performed in close contact with the Expert Team for Visualisation and Reconstruction (ETVR) at the national police of the
Netherlands.
Procedure interactive presentation
The interactive presentation is developed in HyperText Markup Language (HTML) and Cascading Style Sheets (CSS). HTML and CSS can be written using many editors. For example Notepad,
Sublime Text and Adobe Dreamweaver. Within the project, Adobe Dreamweaver is chosen because of its user friendliness and its availability at the department of the Expert Team of Visualisation and
Reconstruction (ETVR) at the national police where the interactive presentations were made. The procedure to develop the interactive presentation has been described by Kieboom [6]. However, since the procedure has been improved, a renewed version will be described here. To speed up the
development of the interactive presentation and to make sure that someone who is unfamiliar with HTML and CSS will be able to create the presentation, a template presentation has been created. This template only has to be filled in with the specific pictures and information of the case. For every command of the script, it is explained what the command does and what still needs to be filled in. Explanation of the presentation template
The interactive presentation consists of five main sections; the homepage, the case information, the investigation on the crime scene, the investigation of the body and the reconstruction (Figure 1). As soon as additional reports become available, the presentation is supplemented with this new
information. On the homepage a timeline is shown of the investigation. This includes when the incident took place, when the different reports became available and when the interactive presentation was made. All these different events and their corresponding dates are added to the template of the HTML-file of the homepage (Figure 1,2). On the main page of the case information links should be created to all the available reports in the case. Here, only the titles of the corresponding documents have to be filled in on the template page of the case information.
Figure 2: An example of the code for the timeline in which only the date and event has to be filled in Figure 1: An example of a part of the homepage with the main sections
The next main page concerns the investigation on the crime scene and consists of several tab pages. In the template presentation one can choose the amount of tab pages and their titles. For example, in the test case, the tab pages visualisation crime scene, found ammunition, damages and blood spatter pattern were defined (Figure 3). In the tab visualisation crime scene pictures of the crime scene are shown together with quotes from the report of the crime scene investigators in which they describe the crime scene. These quotes go together with a reference to the document and page that is quoted. Furthermore, screenshots are shown of the three-dimensional model of the crime scene enabling a comparison with the pictures. These screenshots go together with a link to screenshots of the three-dimensional model with the point clouds so one can verify that the model corresponds to the crime scene (Figure 4). Quotes and images can easily be inserted in the presentation, because of the standard text block and image block that have been created in the presentation template. Only the considered text, the document were it is quoted from and the titles of the images needs to be filled in (Figure 5).
Figure 3: Tab pages within the investigation of the crime scene
Figure 4: Comparison model, point cloud and picture
Finally, a link to an application of a tool named VR4MAX is incorporated in the tab
visualisation crime scene. This tool belongs to the same software package as Autodesk 3D Studio Max in which the three-dimensional model is created. In this application one can easily look at the entire three-dimensional model of the crime scene from different perspectives. The application does not require any installed software and runs on every computer. This makes it suitable as a product of the project, since it will be used by multiple parties that are not in the possession of three-dimensional modelling software.
In the next tab page called found ammunition an overview is given of ammunition parts that are found on the crime scene. Of each part that is secured, pictures are shown together with the quoted description of where it was found, what kind of element it is expected to be and how it is secured. Furthermore, this page consists of four tab pages in which the investigation of the weapons and ammunition department was summarised; comparison cartridge cases, comparison bullets and casing fragments, possibly used weapon(s) and National Collection of Bullets and Cartridge cases that contain all the information that is obtained during the investigation of the department of weapons and ammunition (Figure 6).
The following tab page under the main tab of the investigation of the crime scene is about the damages on the crime scene that might be caused by a bullet. Here again quotations are shown together with their reference and clarifying pictures that can be easily created with the use of a text and image blocks from the presentation template. These quotations concern the description of the damage, a description of its location and the tests that have been done on the particular damage. Finally, in the tab page blood spatter pattern the descriptions of the blood spatter pattern are quoted, referring to the report from which a quote is taken and supported with pictures of the pattern.
The next main page contains all information regarding the investigation of the body of the victim. This main page is again made up of tab pages that can differ per case. In this case four tabs are used: visualisation body, skin damages, wound channels and damages clothing (Figure 7). In the tab page visualisation crime scene a screenshot of the radiological model with the wound channels inside the body. Besides, there is again a link to an application of the VR4MAX tool in which the skeleton can be viewed from different perspectives. In the tab skin damages an overview is given of the interpretation and conclusion concerning the skin damages that were observed by the crime scene investigators, the pathologist and the radiologist. Furthermore, this tab is split into the tab pages damages throat, damages thorax and damages left arm (Figure 8). In these tab pages all information in the reports considering the skin damages is mentioned. For each skin damage the descriptions from all different experts, including those from the crime scene investigation, pathology, radiology and gunshot residue department are quoted including the clarifying images from the reports of these experts.
Figure 6: Tab pages of found ammunition
Figure 8: Tab pages within the investigation of the body
In the tab page wound channels the same principle is applied as in the tab page about the skin damages. First an overview is given of the interpretations and conclusions concerning the wound channels. Besides, the page is split up into the different shot channels which are in this case channel A-B, channel C-F, channel D-projectile and channel E-projectile (Figure 9). In these tab pages all information regarding the specific wound channel is quoted and supported with images of the different expertises. The final tab called damages clothing is split up in the damages of the jacket and the damages of the scarf. In separate tab pages the information of the different damages is quoted, referring to the concerning report which is in this case the report of the gunshot residue department (Figure 10).
The final main tab concerning the reconstruction should be split up in tab pages such as
reconstruction of the shot channels, reconstruction of shooting distance and scenarios (Figure 11). In these tab pages visualisations of the reconstructions in the three-dimensional visualisation are shown together with quotes of the statements on which these visualisations are based. In the final tab
concerning the scenarios, the delivered scenarios can be quoted and visualisations of these scenarios are shown. Also links to the corresponding VR4MAX applications that make it possible to view the visualised scenarios from different perspectives may be incorporated.
Procedure three-dimensional model
The three-dimensional model is built on the point clouds that are acquired with the result of 3D laser scans of the crime scene. The 3D laser scanner takes measurements of every point the laser touches. It takes measurements in every direction resulting in millions of points that are measured in every scan. Because of the many measurements taken, the result is a three-dimensional visualisation of the place that was scanned consisting of millions of individual points. As has also been described by Kieboom [6], the scans have to be merged in the program Leica Cyclone, which is 3D point cloud processing software, to form one scan that incorporates the entire crime scene. The resulting file in .pts-format should then be imported in Alice Labs' Studio Clouds which is 3D point cloud editing software that makes it possible to save the point cloud as an .alp-file that can be loaded in the software package Autodesk 3D Studio Max in which the 3D model is built. After importing the point cloud in the 3D modelling software, a model can be created with a number of manual procedures.
Figure 9: Tab pages wound channels
Figure 10: Tab pages damages clothing and damages jacket
2.2 Semi-structured interviews
The second method applied in this study is the semi-structured interview. By means of questioning the participants in a semi-structured interview thorough knowledge and insight is gained which cannot be acquired by means of other methods. Boeije [13] confirms this unique characteristic of the method of interview. The fact that the interviews are semi-structured means some structure is provided by the interviewer to the content, formulation and sequence of the questions. The interviews cannot be considered as open conversations, since they were goal-oriented. However, the interviews are not entirely closed and structured to give the participants the opportunity to formulate their own answers and to add additional information to the interview. Notes were taken during these interviews and worked out in a summary.
The interviews were conducted with five respondents that are used to work in the investigation of criminal cases. One of the interviewees is a forensic coordinator and criminal investigation expert, involved in a project to add the tactical analyst to the crime scene investigation team in an attempt to clarify and enhance the scenario thinking process. Two other participants are crime scene
investigators in case A which was processed within the project three-dimensional visualisations of deadly shooting incidents which was participated in. The final two participants were involved in the investigation of case B that was processed within the project previously; one of them as coordinator of the crime scene unit and the other one as crime scene investigator. The cases are referred to as case A and case B due to confidential reasons. The regarding participants were interviewed to get insight in the way scenario thinking is applied in current practice and to investigate whether certain
visualisations could contribute to this scenario thinking process.
During the interviews, the participants were questioned about their definition of scenarios and the way they make use of these scenarios during their work. Furthermore, the development of the scenarios during the investigation of respectively case A or case B was explored during the interview and visualisations regarding the case were presented. The participants were questioned whether these visualisations could have influenced the considered scenarios they just explained to test the effect of the visualisations. The visualisations included side and floor plans created from the point clouds of the crime scene with and without a standardised human model from the software Autodesk 3D Studio Max called a Biped placed in the point cloud. To create the visualisations that were used during the interviews, the point clouds were imported in Autodesk 3D Studio Max and screenshots were taken. Examples of the used visualisations are given in Figure 12 and 13 below.
Finally, the participants were asked for their vision on bringing the tactical analyst to the crime scene in order to get insight in the weaknesses in the current scenario process and to get insight in possibilities of enhancing this scenario thinking process.
2.3 Internal documents analysis
The final method that completes the triangulation of methods, is the analysis of documents. In this method relevant internal resources that cannot be considered as peer-reviewed academic studies, are analysed. The analysed documents include reports of different expertises concerning a criminal case and theses of students that contain information from interviews about visualisation topics with people from the forensic field. The case reports are analysed to determine whether scenarios are mentioned and visualisations are used to get insight in the way these are documented in the current procedure of a case. The theses of students are analysed on statements about the contribution visualisation can have to scenario thinking.
3.Results
In this section the results from the different research methods are described and analysed. First the results from the participating observation will be explained in section 3.1. In this section general observations are mentioned, followed by the insights that were gained during interviews with experts within the project three-dimensional visualisations of deadly shooting incidents and a description of the procedure of the project in case A. Next, the results of the semi-structured interviews with participants of a forensic investigation team are described (3.2). Finally, the results of the final method concerning the internal documents analysis will be described in 3.3.
3.1 Participating observation
During the participating observation, firstly an old case was picked up that had been assigned to the project. Visualisations had been made in this case, but not all information was collected yet and no interactive presentation was made. Furthermore, a new case was assigned to the project in which could be participated from the start. Therefore, the complete procedure was observed, which made it possible to gain insight in the strengths and weaknesses in the procedure. These will be discussed in section 3.1.2 of this chapter.
While participating in the project, multiple meetings were organised with all participants. During these meetings, the cases that were worked on, were discussed. Also, developments in the procedures of the project and the organisation of a simulation case came by as subjects in the meetings. Discussions concerning how to visualise the victim in the three-dimensional model arose multiple times.
How to visualise the victim
In a case that is assigned to this project, the victim is scanned at the forensic radiology department in the university medical centre in Maastricht. By making this scan a three-dimensional model of the skeleton and the skin is developed. This model is sent to the Expert Team for Visualisation and Reconstruction (ETVR) of the national police in the Netherlands, where the three-dimensional model of the crime scene is also created. At this point, there are two main options to integrate the model of the victim into the model of the crime scene and to be able to visualise potential scenarios.
First of all, one could make use of a pre-programmed simplified human model called the Biped which is part of the software package Autodesk 3D Studio Max that is used to build the
three-dimensional model of the crime scene. This pre-programmed model can be fitted to the model of the skeleton that is provided by the radiology department (Figure 14). The resulting model can be transformed in different postures. Parts of the body can be moved and rotated in a quite natural way. Biological impossible movements are excluded. Therefore, it will not be possible, for example, to rotate the head of the Biped for 180 degrees. Also dependencies between the body parts are incorporated in the model to make sure that the adjacent parts of the body move along with the part that is moved or rotated. For example, when the right upper leg is tilted, the right lower leg, the right foot, and the toes of the right foot will move upwards together with the upper leg.
Figure 14: The fitting of the Biped towards the radiological model
The second main option is to use the original data from the radiology department and to import this in the three-dimensional environment of the crime scene. To make it possible to move and rotate the individual parts of the skeleton, the bones have to be separated manually. Furthermore, the joints that define the pivots or points of rotation of the bones have to be assigned by the user. Also, the dependencies between the different body parts that make sure that dependent body parts move along with the part that is affected need to be defined.
Although Kieboom [6] showed that the use of the pre-programmed Biped is a reliable method that approximates the measures of the radiological model quite well, the opinions within the project three-dimensional visualisations of deadly shooting incidents vary about which of these options is the best. Some prefer the use of the Biped because, in their opinion, using the original radiological data might give the impression that what has been visualised corresponds to the actual situation.
Furthermore, the process of developing the Biped would have a larger degree of reproducibility compared to editing the radiological data.
Supporters of using the original radiological data do not agree on this point. Not using the skin of the victim, but solely the skeleton would already decrease the experience of reality by the user. They prefer to stay close to the original data to minimise the deviation from reality, although the exact measures cannot be traced back. Furthermore, an argument was introduced that editing the
radiological data would be as reproducible as editing the Biped. Using the radiological data would have the advantage that it is not depending on a specific software package, contrary to the Biped that can only be used within Autodesk 3D Studio Max.
Objective project three-dimensional visualisations of deadly shooting incidents
Another discussion that arose during one of the meetings with all participants, concerned the final objective of the project. In processing several cases within the project, discrepancies between different expertises were discovered. Aiming at combining the results of all experts, all information within a case is read again and discrepancies might be discovered. The question is how to deal with these
discrepancies within the project. Some state that meetings with the involved experts should be organised, resulting in a report which states what finding is most likely in order to solve the
discrepancy. Others argue the task of the project members stops at the discovery of the discrepancy, since comparing expertises is beyond their expertise.
3.1.1 Interviews with participants of the project
To get insight in the way the different experts involved in the project three-dimensional visualisations of deadly shooting incidents think about scenarios, interviews were organised with each expertise. These interviews concerned the contribution that each expertise can have in a case, their vision on the use of scenarios and their vision on the timing of the use of the interactive presentation as developed in the project. Remarkably, these interviews did not provide much inside information about the vision of the experts towards scenarios; how to define and visualise them. Touching the subject, almost every participant tried to avoid it and explained that scenarios are outside of their expertise. During the interviews, the impression arose that scenarios are seen as a taboo subject that can only be
discussed by judges.
In the interviews, also the old case that was worked out during this research was discussed. The experts summarised the most important findings of their investigation in the case that should be included in the interactive presentation. Remarkable was how the different expertises contributed to each other without knowing it. One of the experts explained, for example, that the formulation of relevant scenarios and visualising these could become extremely difficult, because based on their report, it was not possible to give a statement about which weapon fired the fatal shot. However, when talking to other expertises and combining their findings, it became clear that this was possible. Hereby, the strength of combining the results of different experts was emphasised.
Finally, the participants were asked for their vision on the idea of using the interactive presentation in an earlier stage of the investigation. The main message was that it would certainly be useful, but difficult to achieve. To develop the interactive presentation, information of all different expertises has to be collected which requires the permission of the public prosecutor and the
examining judge. This procedure can take weeks or months, which would make it impossible to launch the interactive presentation in an early stage. Despite this practical matter, the participants agreed on the usefulness of early visualisations. These visualisations could raise questions to the investigators of the case that give new opportunities for the investigation.
3.1.2 Procedure case A
In the following paragraphs the procedure of case A, that was assigned to the project three-dimensional visualisations of deadly shooting incidents, will be described. At the end of the description, in Figure 15, a timeline of the procedure is given.
Application of the case
During the project meeting on the 10thof March, the members of the project heard for the first time about the application of case A for the project. During this meeting, it was discussed whether the case fitted in the project. Unanimously it was decided to proceed with this case and to work out
visualisations and an interactive presentation. Criteria for a case to be assigned to the project are the following:
The case concerns a deadly shooting incident;
Three-dimensional laser scans have been made at the crime scene;
A full body CT-scan of the body of the victim is made at for example the forensic radiology department of the University Medical Centre of Maastricht;
An autopsy has been or will be performed on the body.
Besides, it should be considered whether visualisation might contribute to the regular investigation of the case. Case A met these criteria and agreements were made about how to proceed with this case. Case A is the first in which the project participates during the investigation. In the other cases the visualisations and the end product were made some time after the initial investigations in the case.
It was agreed that all members of the project would search for investigations that had been done or will be done at their department for case A. Also, it was decided to invite the colleagues of case A to inform them about the possibilities within the project three-dimensional visualisations of deadly shooting incidents and to hand over the application and permission forms. The permission form has to be signed by the public prosecutor of the case to provide the members of the project with all information, pictures and reports of the case. It was decided was that a delegation of the investigating team of case A and the public prosecutor of the case would be invited. Of the members of the project, the people who would be working on the visualisation, and the project manager would be present at this meeting.
Meeting delegation case A
In the end of March, the meeting took place. Unfortunately, the public prosecutor was not able to attend this meeting. During the gathering, the present project members explained the workflow of the project and the possible contribution that it could have in the investigation of a deadly shooting
incident. Also, an example of the end product for a previous case was presented. The members of the investigating team of case A responded enthusiastic and were confident about the relevance of the project to the case. Furthermore, the delegation of case A explained some things about the case, including what should be achieved with the visualisations; to make a distinction between self-defence and murder. It was made clear that the people of case A could provide the project with the scenarios they wanted to be visualised as soon as possible. It was decided to proceed with the case within the project and the forms for application and permission were handed over to the delegation of case A. They would make sure that these would be filled in, signed and handed over to the project again. Building of the three-dimensional model
After the meeting with the delegation of case A, a start could be made with building the three-dimensional model. This started on the 13thof April and the three-dimensional model of the crime scene was finished around the 20th of April. It was modelled together with a participant of the project three-dimensional visualisations of deadly shooting incidents that was working at the visualisation department of the local investigation team. Usually the 3D laser scans of a crime scene are made by the Expert Team for Visualisation and Reconstruction (ETVR) of the national police in the Netherlands, but in this case the visualisation department of the local investigation team made the scans. In the cooperation with the visualisation expert of the local investigation team during the development of the
three-dimensional model of the crime scene, it was brought up that the delegation of case A, that was invited earlier for an explanation of the project, had trouble in formulating the scenarios that were requested. An interesting fact showing the obscurity and lack of knowledge about what a scenario consists of.
The data of the three-dimensional radiological model came in around the 29th of April. One of the visualisation and reconstruction experts started preparing the radiological model by separating the bones of the skeleton. As described in section 3.1.1 this procedure is one of two options. In this case was chosen for the procedure in which the radiological data is edited in order to make it possible to position the skeleton in different ways. This choice has been made, because the visualisation and reconstruction expert, who was dealing with this data, was more acquainted with this procedure than with the creation of a Biped. Furthermore, this visualisation expert is one of the people who preferring the use of the original radiological data instead.
Around the 15th of May, the prepared radiological model with the separated bones came available to import it in Autodesk 3D Studio Max and include the dependencies and movements in the model. This process was finished on the 19th of May. By then, the radiological model of the skeleton was made moveable and was scaled to the size of the model of the crime scene to merge the skeleton with the three-dimensional model of the crime scene.
Interactive presentation of the case
Meanwhile, the reports of the involved experts slowly came available to the project three-dimensional visualisations of deadly shooting incidents. At the 9th of April, the first reports came available and it took until the 17th of June until all reports of the experts were available to the project. This procedure took a long time, comparing the dates the reports were available to the project with the dates that the reports were finished. This could be explained by the fact that some experts of the Netherlands Forensic Institute (NFI) were reporting to the examining judge and could not send their reports directly to the project. First the permission of the examining judge had to be given to share the report with the members of the project. This delayed the process and therefore is decided that a permission form for the examining judge should be created as well.
Furthermore, when going through the report of the crime scene investigation and the attached document with pictures to which is referred in the report, it turned out that the quality of the pictures was very low. The document provided was a scan of the printed pictures that were stuck on a piece of paper. However, because these pictures should be used in the interactive presentation, that might be used in the courtroom in the future, it is important that these are of good quality. Therefore, it was necessary to contact the forensic coordinator and ask for the original digital pictures. To prevent another delay in the creation of the interactive presentation for this reason, it is recommended to formulate clear demands towards the investigating team concerning the format in which the data should be provided to the project. These requirements will be incorporated in the application form in the future.
In the development of the interactive presentation of case A, the presentation template that is described in the Materials & Methods section is used. When it turned out something was missing, the template was updated. In a following case, the presentation template could be used by someone unfamiliar with HTML and CSS to check whether the explanations are sufficient. To be able to develop the interactive presentation of case A, it was necessary to read all reports carefully to filter out the information that should be incorporated. When something was unclear, the concerned expert was contacted. In the future, a procedure can be created in which the expert announces which parts of his report should be quoted in the interactive presentation. This will prevent information that is important according to the expert from not being incorporated in the product. Also, it will quicken the procedure, since not all reports have to be read in depth by the developer of the interactive presentation. In the procedure of case A missing important information was prevented by asking feedback of the experts at the time the interactive presentation was ready.
The final main page of the interactive presentation regarding the reconstruction could not be filled in for a long time, since the reconstructions are dependent on the questions of the investigating team and the scenarios they are interested in. In case A, it took a very long before scenarios could e
discussed with the investigating team. As mentioned before, it turned out that the forensic
investigators experienced difficulty in formulating the scenarios, since they could not provide us with details of the activities that might have taken place. Finally, it was decided to invite the people from the investigating team of case A for a meeting with the project members to show the interactive
presentation and the visualisations, and to give them the opportunity to present their scenarios. However, the forensic coordinator brought this to a halt. Scenarios could only be provided to the project three-dimensional visualisations of deadly shooting incidents when both the public prosecutor as well as the defence was given this opportunity. Therefore, first a meeting had to be organised with the examining judge, the public prosecutor and the defence lawyer.
Meeting with the examining judge, public prosecutor and defence lawyer
Prior to this meeting, which was planned at the 9th of July, the interactive presentation including the information of all expertises was presented to the members of the project. By this presentation, it could be verified whether sufficient information was incorporated of all expertises. Also, the opportunity was created to give some suggestions to optimize the presentation. This presentation to the members of the project was given on the 30th of June. A few suggestions were given, including the suggestion to request for an additional report of the forensic investigation team in order to fill a gap in the information that was included in the presentation. The forensic coordinator was contacted to request the additional information that was necessary to present a solid product to the examining judge, public prosecutor and lawyer. Remarkably, it turned out that the forensic coordinator was on holiday and that no-one else knew enough about the case to provide the project with the requested information. Although the meeting with the examining judge, public prosecutor and lawyer was planned by the forensic
coordinator, due to the holidays, he could not attend this meeting himself. At the moment this was found out, it was decided that during this meeting the content of the case could not be talked about.
Eventually, a presentation was given during the meeting at the 9th of July about the objectives and the workflow of the project. Also, an example of the end product was shown. During these presentations a lot of questions were asked, illustrating that the clarity of the visualisations towards laymen, could still be improved. Despite the needed clarifications, the reactions were positive. Especially the examining judge and the public prosecutor saw opportunities for case A. It was mentioned that scenarios they wanted to be visualised, could be provided to the project as soon as possible. Both the examining judge and the public prosecutor stated that they were already thinking of some scenarios that could be visualised. However, the defence lawyer stated it was not possible to visualise any scenario, because a struggle had taken place. Therefore, he would not provide any scenarios.
Optimising the visualisation
Although the examining judge and public prosecutor promised to provide us with scenarios, it took quite a long time before these scenarios reached us. Over a month after the meeting, on the 13th of August, the scenarios were provided to the project three-dimensional visualisations of deadly shooting incidents. Meanwhile, the visualisation was extended in such a way that it would be ready for a reconstruction. Wound channels inside the body were lengthened with a standard deviation of five degrees, the damages on the crime scene were indicated and the ranges of the distance in which the shot had been fired were visualised. The members of the project decided to plan a meeting on the 18th of August with people working on case A. During this meeting the product so far was presented, including the interactive presentation and some images of the three-dimensional visualisation. From the investigating team of case A the forensic coordinator, the tactical leader, the project leader and delegate of the prosecution counsel were present. The reactions after the presentation were positive. It was decided to organise an expert meeting with the involved expertises in the case.
During such an expert meeting, the visualisation could be optimised and the scenarios could be visualised. All different experts could verify whether their expertise was rightfully visualised and additional insights could be included. Bringing these experts together, a valid visualisation can be created that shows the boundaries of what could have happened. Together, the scenarios could be visualised and each expert could determine from his own expertise whether these scenarios
technically could have happened. In order to make this meeting possible, an expert nomination of all relevant experts was carried out by the examining judge to justify a meeting of experts in which scenarios are discussed. The examining judge was very strict in separating the experts from the police investigators. Therefore, no crime scene investigators can be invited to this first expert meeting. However, it could be more efficient to have these investigators in the first meeting as well, because it is expected that they know more than what can be read in the reports, including technical information that would be useful in the visualisation. Therefore, the outcome of the first meeting could be a number of arguments for the examining judge to organise a second meeting with the crime scene investigators to give them the opportunity to verify the visualisation of the scenarios.
11/2 incident
request radiology 12/2 request pathology
guiding report radiology 13/2 request toxicological research 16/2 request ammunition research
report CSI finished 19/2 report pathology finished 10/3 case discussed in project 11/3 toxicological report finished 28/3 presentation project case A 09/4 report CSI at project
guiding report radiology at project report pathology at project 13/4 started building 3D model 17/4 report ammunition finished
report ammunition at project 20/4 report radiology finished
3D model crime scene finished 29/4 radiological model at project 15/5 radiological model separated 19/5 radiological model scaled
radiological model moveable 17/6 report gunshot residue at project
report radiology at project 30/6 presentation product project 08/7 urgent report gunshot residue at
project
09/7 meeting examining judge 13/8 scenarios at project
18/8 presentation product case A
../9 expert meeting for visualisation scenarios? ../9 meeting crime scene investigators for
visualisation scenarios?
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3.2 Semi-structured interviews
In the following section, first the interview with a member of a pilot project, in which the tactical analyst is brought to the crime scene to enhance the scenario thinking process, will be described. Next, in 3.2.2 the interviews with investigators in case A are described, followed by the summary and analysis of the interviews with investigators in case B.
3.2.1 Tactical analyst to the crime scene
During this research it was experienced that it was difficult to talk about scenarios. Talking with the different participants within the project three-dimensional visualisations of deadly shooting incidents, it turned out that most people were not willing to talk about scenarios, since this was beyond their expertise. In an interview with a forensic coordinator and criminal investigation expert, was talked about a pilot project in which he is participating. In this pilot, the tactical analyst is brought to the crime scene to enhance the scenario thinking process. During this interview, the interest arose in the experiences within the pilot project concerning the communication about scenarios.
The role of the tactical analyst
A tactical analyst comes into play when a case is assigned to a TGO team, where TGO stands for Team Grootschalig Opsporing or Team Major Investigation. A case is assigned to such a team when the committed crime can be considered a capital crime. A capital crime is characterised by a(n) (possible) intentional homicide, a severe sexual offence, an arson with severe consequences, a hostage, a kidnap or another offence against the physical integrity of the victim. To be considered a capital crime, the penalty must be a prison sentence of twelve years or more. Furthermore, the case must be expected to have a large impact on society and it should be impossible to identify the
perpetrator unambiguously [15]. When a particular case meets all of these requirements, it is assigned to a TGO, in which a tactical analyst takes part. A TGO works according to a fixed structure in which the tactical analyst is reporting to the team leader and contributes in this way to the decision of the team leader about the direction of the investigation. Indirectly, the tactical analyst also has an advising role to the rest of the team. An overview of the structure of a TGO can be found in Figure 16.
The role of the tactical analyst is structuring the information and the scenarios that are available in a case, to keep up with the possible directions of the investigation, to weigh these different scenarios, and consider whether they are realistic or not. Thus, the tactical analyst is actively considering the possible scenarios. Usually the tactical analyst makes use of a mind map, in which the scenarios are worked out in several elements.
Reasons for pilot project
The interviewee told that both the tactical analyst and the forensic investigators experienced difficulties in the regular structure of the TGO. Tactical analysts could not define the scenarios of the forensic investigators. Since the tactical analyst is not aware of the context in which traces are secured at the crime, scenarios were formulated that did not fit the technical traces. Furthermore, the tactical analyst had no insight in the alternatives that were investigated during the investigations at the crime scene. Another disadvantage that was experienced, is that there is no opportunity to investigate the scenarios that a tactical analyst formulates at the crime scene. Finally, the tactical analyst experienced difficulty in determining the effect of a result of the investigation on the probability of the different scenarios.
Also within the forensic investigation team, some difficulties came across according to the interviewee. Although crime scene investigators collect traces based on sophisticated reasoning, it seems to be some sort of mystery to outsiders what they are doing. Forensic investigators perform their 'magic trick' and no one else knows exactly what they are doing and for what reason. This raises a lot of questions towards the forensic investigators after their investigations. Also, a severe difficulty was experienced by the investigating team in combining the results of the technical traces with the tactical scenarios that were formulated. There seemed to be no relation between these traces and scenarios. To overcome these difficulties, the idea came up to let the tactical analyst join the investigators at the crime scene.
Experiences in the pilot project
This pilot project was set up a couple of years ago and during this period ten TGO cases were handled according this setup. During the crime scene investigation, the tactical analyst contributed by working out the considered scenarios in detail. With these scenarios, it was made possible to apply a method that is referred to as scripting by the respondent. Using this method, in the parts the scenario consists of is looked for clues for the forensic investigators to falsify the scenario. When it is indeed possible to falsify one or more steps within a scenario, based on traces that are or are not found, the scenario can be eliminated. However, when it turns out that the elements of the scenario cannot be falsified, based on the traces at the crime scene, this strengthens the scenario. The strength of applying this method directly at the crime scene, is that the results of the traces can be easily linked to the scenarios. This link was previously missing and is therefore a valuable contribution to the original procedures.
Another advantage of bringing the tactical analyst to the crime scene experienced during the pilot project is that the tactical analyst can have input in the action plan of the forensic investigators. Also, the tactical analyst can get a complete impression of the case. The plan of action concerns what the investigators are going to do on the crime scene. This can only be decided, knowing what you want to be investigated, which is implicitly based on scenarios about what might have happened. Furthermore, by listening carefully to the investigators on the crime scene, the tactical analyst collects a lot of information that was otherwise made available in a later stadium without knowing where the information exactly came from. The tactical analyst now even gets the opportunity to think along with the investigators at the crime scene and can ask questions and give suggestions for the crime scene investigation. The process becomes transparent, since it is made explicit which decision are made and for what reason. Usually, this was only known by the forensic investigators and was not made explicit by incorporating this in a report.
Despite all the advantages that were experienced in the project, also some difficulties became apparent. For example, it turned out that forensic investigators experience difficulty explaining their thoughts during their investigation and why some decisions were made. The investigators are not used to explicitly think about scenarios, although is assumed that every forensic investigator makes use of scenarios during their work at the crime scene. Probably, they weigh all information implicitly during
their investigation instead of making this explicit. The interviewee explained that explicitly thinking in scenarios may be too abstract for the forensic investigators, because a scenario goes beyond the facts, taking the story behind the facts in account. This is contrasting to the tactical analysts, who are used to make the scenarios explicit. In some instances tension arose between the forensic
investigators and the tactical analyst at the crime scene. The tactical analyst is forcing the forensic investigators to make their implicit thoughts explicit by asking questions. This resulted in frustrated reactions of the investigators. According to the interviewee, it seemed to the forensic investigators as if the tactical analyst was only extracting information from them and did not contribute to the
investigation at the crime scene, since the tactical analyst has no inside knowledge about the technical investigation they performed. Therefore, the impression can rise that the tactical analyst is only
slowing down the investigation instead of improving it. Contribution of visualisations
The forensic coordinator and criminal investigation expert was also questioned about the contribution visualisations could have on the scenario process. The participant thought that visualisations could contribute for sure. He stated that scenarios should be formulated first after which they could be visualised to be tested. He said that it would not be efficient to inconsiderately start visualising and to think of scenarios afterwards. However, later on in the interview the participant mentioned that visualisations like floor and side plans with correct ratios, could be very useful in presenting the investigation and scenarios to the other coordinators and the leader of the investigation during the crime scene investigation. The findings of the forensic investigation team could be explained more clearly by means of these visualisations. The coordinators and leader of the investigation could see for themselves what the crime scene looks like and decide whether they think all necessary investigations are done and the crime scene could be made public again. By using the visualisations, they could test for themselves whether the proposed scenarios were feasible and could think of additional scenarios. For this purpose, an image of the point cloud would be sufficient according to the interviewee.
3.2.2 Semi-structured interviews case A
To gain more information and insight in the way scenarios are treated within the crime scene
investigation, interviews were organised with two crime scene investigators who were involved in the investigation of case A. In these interviews the first concerned the vision of the participants on
scenarios; what they think defines a scenario, who is working or should be working with scenarios and what the contribution of certain visualisations could be on thinking in scenarios. During this
conversation, it was possible to experience whether these crime scene investigators have difficulty speaking of scenarios as was experienced within the project of bringing the tactical analyst to the crime scene and in the interviews with the experts within the project three-dimensional visualisations of deadly shooting incidents. Finally, the participants were asked for their thoughts about the project in which the tactical analyst is brought to the crime scene.
The use of scenarios
On the question what they thought a definition of a scenario is, both of the participants responded somewhat giggly. The exact answer to this question is unknown to everyone, they explained. Despite this, they state that they have an image of scenarios and think it is useful to take the scenarios in account during the investigation. Later on in the interview, one of the participants named the perpetrator, type of crime and motive as elements of a scenario. Furthermore, both the participants emphasised that the considered scenarios should be practical and should not be made only because they need to be made. Sometimes they get this impression, because the tactical department creates up to thirty or even sixty scenarios that cannot all be realistic and practical. Apparently, tactics and forensics have a different view on scenarios.
According to these two participants from case A, one takes into account multiple scenarios during the investigation on the crime scene. As an example, one of the participants explained that, after a shooting incident, they might test whether the victim had fired a gun by sampling his or her
hands, since the victim could also have fired a shot during the incident. This is the way in which the crime scene investigators are working with scenarios on the crime scene. They are not considering a complete story, which might be the idea of a scenario within the tactical department, but instead they consider separate activities that might have taken place at the crime scene. Based on these
considerations, traces are secured, to be able to test these scenarios or activities. The scenarios they think of during their investigation stay as close to the facts as possible. They are looking at the traces on the crime scene and try to link these to possible activities that took place during the incident and do not consider any tactical information.
The crime scene investigators are not aware of the further process of the scenarios. They are not informed about developments in the case and are therefore not involved in the process of
formulating scenarios. The two participants regret this and think it would be better when crime scene investigators were more involved in the further investigation of the case. This would make it possible to formulate scenarios based on the traces that were found at the crime scene; the way forensic
investigators deal with scenarios. According to both interviewees this would decrease the amount of scenarios drastically; instead of one hundred scenarios one might now only have three. Sometimes, the crime scene investigators came across a document of scenarios, in which scenarios were mentioned that were technically not possible based on what they had seen on the crime scene.
The other way around, the scenarios that the crime scene investigators think of during their investigation are communicated to others. During the investigation at the crime scene are many meetings with the coordinator of the crime scene unit, who reports as much as possible in the journal that he keeps up. Thereby, the decision moments and underlying scenarios that are thought of are not kept for themselves but could be placed on record. However, it is questionable to what extend all this information is documented and is used in the formulating of the eventual scenarios. Practice has shown that the formulated scenarios do not always match the traces that were found at the crime scene.
Contribution of visualisations
During the interviews several visualisations were shown to the participants and they were asked whether these could be useful. First, visualisations were shown of solely the point cloud which could be used as a plan of the different floors and the side views. These visualisations could be available in a very early stage in the investigation; already during the crime scene investigation. Both the
participants stated that visualisations as the ones showed, are extremely important in the
communication between the tactical and technical investigation teams, to prevent misunderstandings. However, they did not see any added value of the visualisations during the crime scene investigation. Also, when visualisation were showed that included a Biped that could be placed anywhere in any position, both the participants did not see any use of these during the crime scene investigation. They explained that they do not need it, since they are at the crime scene and can take any position there to get an impression of possible scenarios that could help them in finding and securing relevant traces.
Also for other people that are involved in the investigation at the crime scene, both participants saw no added value of the visualisations. The crime scene investigators can sketch what they had seen on the crime scene to give the rest an impression of the arrangement of the crime scene. More than an impression is not necessary according to the interviewees. Pictures taken at the crime scene or 360 degree recordings of the crime scene could help to get an impression, however exact ratios of everything will only become important when one wants to test scenarios, which is not happening in the stage of the crime scene investigation. Furthermore, the participants emphasised that the crime scene investigation is executed very accurate and extensive and that there is very little chance that any trace will be missed. Therefore, the use of the visualisations would not contribute in the search for traces that would otherwise be missed. In the interpretation of the traces, the visualisations could be extremely important, but this process starts after the crime scene investigation.
Despite the fact that the participants did not see any added value of the shown visualisations during the crime scene investigation, they did see a great added value of the visualisations in the further investigation, especially in the tactical investigation. According to the interviewees, one should start with the visualisation as soon as the data of the three-dimensional scan of the crime scene and
the radiological data of the victim are available. They state that visualisations as shown could not only contribute in testing the scenarios, but could also help in formulating scenarios. In their opinion, such visualisations could in this particular case indeed have contributed to the process of formulating scenarios.
With the use of these techniques, it could be possible to get together and sketch some hypothetical firing-lines and move the human model around in the virtual crime scene to get insight in the limits of what might have happened. This could already be done with the use of the point clouds. Both participants agreed that the three-dimensional data of the crime scene and the victim should be used as soon as possible after the crime scene investigation. Hereby, visual insight in the way the crime scene looked can be gained, the development of scenarios can be advanced and the reports of the forensic investigators can be clarified. The use of the visualisation will, according to the
interviewees, make sure that everyone is talking about the same things and will prevent differences in interpretation of the results.
Pilot project tactical analyst on the crime scene
Finally, the participants were asked for their thoughts of the project in which the tactical analyst is sent to the crime scene. One of the interviewees reacted extremely surprised and referred the department Ernstige delicten or Severe crimes that was part of the police in Amsterdam. At the time of its
existence, tactical detectives went to the crime scene together with the technical detectives and conducted a verbal report while they accompanied the crime scene investigators. According to the interviewee, the idea behind this was to bring the tactical and the technical investigations together. These tactical people spoke the language of tactics, but had also gained some understanding of the technical aspects. This department of severe crimes is abolished after several years, because it did not work out well. The mentioned project about bringing the tactical analyst to the crime scene sounds to the participant as another attempt to execute the same idea, although it has already turned out that it does not work.
Both the interviewees agreed that it is important to make the thoughts of the crime scene investigator more explicit, including the motivation behind decisions that are taken which illustrate the scenarios that are thought of. They acknowledge they should name and explain more of these decision moments in their reports. Reasoning behind things you do or do not do during the
investigation on the crime scene should, according to these participants, in any case be reported in the journal of the coordinator of the crime scene unit. Additionally, important decisions should be explained in the report of the crime scene investigators themselves. The interviewees confirmed that the scenario thinking of the forensic investigators mainly happens inside the heads of the
investigators. There are meetings in which these lines of thought are discussed, but not everything will be captured. The notes that are taken during the meetings with the coordinator of the crime scene unit and the forensic coordinator, are not always that extensive. Therefore, information about the scenario thinking process of the forensic investigators might get lost.
Although the participants think that decision moments should be recorded more carefully, they question whether this should be done by a tactical analyst. In their opinion, it would be better when this problem is solved within the forensic investigation team. As forensic investigators, they
experienced that in cases where they needed to explain something of to someone from the tactical investigation team, the information changed; nuances within their forensic investigation get lost. A suggestion was made to replace the tactical analyst with a forensic analyst, who understands their technical investigation. Another suggestion made was to incorporate reporting of the lines of thought as part of the job of the coordinator of the crime scene unit or his administrative assistant, because he is responsible for the journal. A third alternative would be to get together as crime scene investigators with the tactical team, and discuss the scenarios they have formulated to see what the forensic investigators can say about these. This way, one prevents scenarios that are technically not possible, based on the traces that were found at the crime scene, from being incorporated. A final option that was mentioned was to use body cams on the crime scene investigators to record everything. When questions arise afterwards, one could make use of these recordings.
